The Cat in the Hat

The Cat in the Hat, by Dr. Seuss (Random House, 1957), which we read to our two-year-old almost every day, is a delight.
1. A wonderful fantasy:  two children are alone on a "cold, cold, wet day" and the Cat in the Hat drops by to do some wonderful, impossible tricks and even cleans up before he leaves and mother comes home. 
2. Psychological complexity.  The Cat obviously represents the id, while the superego is played, in the absence of the mother, by the fish (a natural antagonist of the Cat), who says, "He should not be here when your mother is out."  The Cat brings two companions in anarchy, Thing Two and Thing One, who even fly kites in the house.
3. Delightful characters.  The Cat is obviously in the great American tradition of the charming con man while the fish plays, quite charmingly, the guardian of order.  Sally and her brother stand by, both of them enjoying the chaos until their mother is on her way home, at which time they have to capture Thing One and Thing Two and send the Cat on his way, though he quickly comes back to clean everything up.
4. Complex relationship between text and illustrations. The pictures and the words are in a constantly fluctuating relationship, often combined on the same page, and there is a constant sense of movement conveyed by the way the protagonists are viewed.  There are even somewhat subtle visual touches that indicate this is a fantasy of the children, e.g., Sally's hair ribbon and the Cat's bowtie are a visual match.
When the mother returns things are just as she left them, the children having spent the day at home sharing a fantasy of anarchy.  The book itself is an impressive and playful poem that exists on multiple levels, probably one of the reasons some children never get tired of it.  Even for Dr. Seuss it is unusual in its complex narrative and endlessly playful illustrations.